Mulch & Gravel Calculator: How Much Do I Need?
Mulch and gravel are sold two different ways — bags at the garden center and bulk by the cubic yard or ton — and converting between them is where every DIYer's math falls apart. This free calculator handles both: enter your bed, path or patio size and depth, choose mulch or gravel, and it tells you exactly how many bags, cubic yards or tons to order, plus the estimated cost. Never under-order and make a second delivery trip again.
Mulch & Gravel Quantity Calculator
How to Use This Mulch & Gravel Calculator
Measure the length and width of the bed or patio in feet, and decide on your depth in inches. For mulch around plants, 3 inches is the standard. For a gravel patio or path over compacted soil, plan 4 inches.
Pick your material. For mulch the calculator gives you bags (based on the common 2-cubic-foot bag) and cubic yards for bulk ordering. For gravel it gives tons, using the density of your stone type — pea gravel is lighter than crushed stone. If you know the price, enter it for an instant cost estimate, then click Calculate.
The Mulch and Gravel Calculation Formula
Both materials use the same volume math: cubic feet = length × width × (depth ÷ 12), and cubic yards = cubic feet ÷ 27. From there the paths split: mulch bags = cubic feet ÷ 2 (a standard bag holds 2 cubic feet), while gravel tons = cubic yards × density (about 1.4 tons per cubic yard for typical gravel).
Worked example: a 10 × 10-foot flower bed at 3 inches deep holds 10 × 10 × 0.25 = 25 cubic feet, or 0.93 cubic yards. In bags: 25 ÷ 2 = 12.5 — so 13 bags of mulch. The same area as a 4-inch gravel patio is 33.3 cubic feet (1.23 cu yd), which at 1.4 tons per cubic yard means 1.7 tons — order 2 tons and the extra will disappear into compaction within weeks.
Pro Tips for Ordering Mulch and Gravel
Bulk beats bags on price for anything sizable, but bags are easier to carry, store and move around a fenced yard — if a delivery truck cannot reach your garden gate, bags may be the only option that does not end in a wheelbarrow marathon.
Order gravel with 10 to 15% extra for compaction; the first rain settles it visibly. Lay landscape fabric under gravel paths and patios, or weeds will find the layer within a season. For mulch, refresh the top 1 to 2 inches each year rather than adding more depth — old mulch keeps doing its job of holding moisture and suppressing weeds if you just top it up.
Frequently Asked Questions
How much mulch do I need for 200 sq ft?
For a 200 sq ft bed at the recommended 3-inch depth you need 50 cubic feet of mulch. That is 25 bags of the common 2-cubic-foot bag, or just under 2 cubic yards if you order in bulk.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 bags of the standard 2-cubic-foot mulch bag. Bulk delivery by the cubic yard is usually much cheaper than bags for anything over 10 bags or so.
How much gravel do I need for a 10x10 patio?
A 10x10 patio at 4 inches deep is 33.3 cubic feet, or 1.23 cubic yards. Gravel is sold by the ton, and at the typical density of 1.4 tons per cubic yard that is about 1.7 tons — order 2 tons to allow for compaction.
How deep should mulch be?
Spread mulch 2 to 4 inches deep, with 3 inches the sweet spot. Any deeper and you risk suffocating plant roots and encouraging rot at the base of stems. Keep mulch pulled back an inch or two from trunks.